1. Field of the Invention
The present general inventive concept relates to a head chip for an ink jet type image forming apparatus, and, more particularly, to a head chip with an improved cooling structure.
2. Description of the Related Art
An ink jet type image forming apparatus refers to an apparatus to form an image by ejecting fine ink droplets onto a desired position on a printing medium. Such an ink jet type image forming apparatus is generally classified as an electro-thermal type and a piezoelectric type. The electro-thermal type ink jet image forming apparatus generates bubbles in the ink using a heat source provided at a head chip, and ejects ink droplets through nozzles formed at the head chip using expansive power at the moment of generation of the bubbles.
A head chip for an ink jet type image forming apparatus includes a substrate configured as a silicon wafer and formed with an ink supply port, a channel forming layer disposed on the substrate to form a channel and ink chambers, and a nozzle layer disposed on the channel forming layer and formed with nozzles corresponding to the ink chambers. A substrate layer in contact with the channel forming layer is provided with heaters for ink ejection to form bubbles by heating ink stored in the ink chambers.
Recently, a distance between the nozzles and a firing pulse rate applied to the heaters for ink ejection have been gradually increased, in order to achieve an image of high quality and an increase in printing speed. Accordingly, a problem of adequately maintaining a temperature of the head chip becomes critical. If a distance between the nozzles and a firing pulse applied to the heaters for ink ejection are gradually increased, energy accumulated in the head chip is increased, which causes temperature rise of the head chip. As a result, properties of the ink may be changed, and printing quality may be deteriorated.
A conventional ink jet type image forming apparatus is constituted such that heat is dissipated through a metal head chip, or a head chip is cooled down by attaching an additional cooling member to the head chip. However, dissipating heat through a head chip is inefficient, and attaching an additional cooling member to a head chip reduces productivity and space efficiency.